【作者】 曲宁宁；

【导师】 杨葆和； 金强；

【作者基本信息】 中国舰船研究院 ， 船舶与海洋结构物设计制造， 2011， 硕士

【摘要】 肥大型船在当今运输船型中占有相当大的比例,开展肥大型船的线型研究具有重要的意义,本文的研究对象即为肥大型船的尾部线型。对普通单桨船,由于尾部线型对推进效率的影响比对阻力的影响大得多,尾部线型设计在关注阻力的同时,更多的是追求如何为螺旋桨设计提供一个良好的输入条件,进而提高推进效率。与U形尾及V形尾设计相比,设计优良的球尾可以使螺旋桨盘面处周向伴流分布较均匀,并可减小推力减额,从而既提高了推进效率,又可以减少螺旋桨激振力,改善尾部振动。但由于球尾的控制参数较多,尾部横剖线又有多种形状,球尾与横剖线可以有多种过渡组合,带球尾的尾部线型设计并不轻松。数值计算已成为船体线型优化必不可少的手段。对于粘性起主导作用的船舶尾流场,必须采用粘流计算,其中雷诺平均N-S方程方法(即RANS方法)最常见,通过构造适当的湍流模式,RANS方法已成功解决了大量工程实际问题。PARNASSOS即是一种以RANS方法为核心、主要求解船舶尾流及伴流场的粘流计算软件,其突出特点是在保证一定计算精度的前提下有着非常快的计算速度,并且可用于实船尺度下的计算。为了研究尾部线型对肥大型船尾部流场的影响,本文选取了两艘散货船、一艘油船作为母型船,系列变化其尾部线型,线型的调整既包括对尾部横剖线整体的调整,也包括对球尾及其外围线型的单独考虑,另外还研究了中纵剖线形状的影响。计算在结构吃水的对应航速下进行,对模型尺度和实船尺度都进行了计算。最后对计算结果从粘性阻力和伴流质量两方面进行了分析和总结,力求掌握减小肥大型船的粘性阻力和改善伴流场分布的线型优化方向,以指导工程实际,更好地为船舶总体设计服务。更多还原

【Abstract】 Full-formed ship is the main ship form in today’s cargo carrier, and research on such ship’s lines is of great importance. This paper mainly deals with afterbody lines of full-formed ships. For usual single-screw ship, afterbody lines affect the propulsion efficiency much more than the viscous resistance, the design of ship stern is then to make a good starting point for propeller, thus improve the propulsion efficiency. Comparing with U- and V-shaped stern, the incorporation of stern bulb on full-formed ship could provide more uniform circumferential wake distribution at propeller disk, which on one hand reduces the propulsion deduction, increases the propulsion efficiency and on the other hand, stern vibration would be reduced by the decrease of propeller exciting force. But because of the complicated match of stern bulb with afterbody lines, it’s not an easy job concerning design of afterbody lines.Numerical calculation has been playing an important role in ship’s hydrodynamic optimization. For ship stern flows, viscous flow calculation has to be taken, in which solving the Reynolds-averaged Navier-Stokes equation (RANS method) is quite normal. By constructing proper turbulence model, RANS method has proved to be very successful in practical engineering applications. PARNASSOS is such a RANS code dedicated to predict the steady turbulence flow around ship hulls with very fast calculation speed and good precision. Full-scale calculation is PARNASSOS’another main characteristic.In this paper, two bulk carriers and one tanker are chosen as models for the calculation. Various transformations of afterbody lines including stern bulb, section lines and profile are generated. All calculations are done using PARNASSOS at scantling draught and its corresponding speed. Both model and full scale calculation are performed. Analysis is finally made with respect to both resistance and wake field quality. It hopes that this paper can provide some useful information on the hydrodynamic optimization of full-formed ship.更多还原